In the prevailing down-size trends in the electronic apparatus industry, the multi-layered circuit boards are requested to be smaller in size and thinner, at the same time to be more precise in the dimensional accuracy. Japanese Patent Laid-Open Application No. Hll-45955 discloses a small-size wiring board which contains semiconductor devices and electronic components (capacitors, resistors, filters, oscillation elements, etc.) within the inside. The above described conventional wiring board is formed of a thermosetting resin and a composite material containing a thermosetting resin as the main ingredient. The constituent substrates are laminated while respective substrates are in the soft state (uncured- or half-cured state). They are cured all at once after being laminated. Since respective substrates are still to be cured at the stage when they are laminated, they are easily affected by the influence of forthcoming thermal expansion/shrinkage during curing process.
Namely, reliability in the connection between internal electrodes tends to be poor. Furthermore, it is not easy to eliminate an air gap around the built-in components, which air gap can be generated as a result of dimensional change among the constituent substrates. This means that the reliability can be deteriorated also by humidity in the air. The present invention aims to reduce the dimensional shift due to the high temperature, which dimensional shift arising out of the process for curing a laminated body. Thereby, a high reliability in the connection among the laminated layers maybe secured. Also aimed by the present invention is to offer a small module component in which a plurality of components is built-in precisely and densely.